Structural engineered living materials

Biological structural materials not only exhibit remarkable mechanical properties but also often embody dynamic characteristics such as environmental responsiveness, autonomy, and self-healing, which are difficult to achieve in conventional engineering materials. By merging materials science, synthetic biology, and other disciplines, engineered living materials (ELMs) provide a promising solution to combine living organisms with abiotic components, thus facilitating the construction of functional "living" materials. Like natural materials, ELMs possess vitality and hold immense application potential in areas such as medicine, electronics, and construction, captivating increasing research attention recently. As an emerging branch of ELMs, structural ELMs aim to mimic living biological structural materials by achieving desired mechanical performance while maintaining important "living" characteristics. Here we summarize the recent progress and provide our perspectives for this emerging research area. We first summarize the superiority of structural ELMs by reviewing biological structural materials and biomimetic material design strategies. Subsequently, we provide a systematic discussion on the definition and classifications of structural ELMs, their mechanical performance, and physiological behaviors. Finally, we summarize some critical challenges faced by structural ELMs and highlight directions of future development. We hope this review article can provide a timely summary of the state of the art and relevant perspectives for future development of structural ELMs.